Optics can also be used in illumination devices to collimate or otherwise direct light from a light source.
Depending on the application, optics for use in illumination devices can be selected for the degree of collimation, the depth of the fixture or the size of the light source used. Such optics may consist of optical elements such as lenses or reflective surfaces to direct the light. The light source is often an incandescent bulb, fluorescent bulb or a light emitting diode.
Light is typically emitted from the light source in all or most directions and interacts with the optical elements such that the light is redirected to form a beam in which all the rays of light are substantially parallel or diverge from the illumination device.
One widespread application for illumination devices is automotive headlamps. In a typical automotive headlamp, a bulb is positioned at the focal point of a parabolic reflector. Light emanates from the bulb in all directions and some of the light impinges upon the parabolic reflector, which collimates the light into a beam. The typical automotive headlamp also has a lens for dispersing the collimated light. In general these automotive headlamps have considerable depth, occupying space in the car. Other exemplary applications include products such as, amongst others, stage lighting, flashlights, medical lighting and dentistry lighting.
An efficient illumination device emits a large percentage of the light output by the light source in the desired direction. The design of the optic within an illumination device can affect the size of the device, the ease of manufacture and the device's stability over time.
Therefore, a slim-profile optic that provides directed light in a highly efficient manner is desirable for use in an illumination device.